SailGP's first day of racing was abandoned on Saturday after a dolphin was spotted on the course. Photo: Supplied/SailGP

The cancellation of the first day of the SailGP event is a good thing because the races are being run in a poor location, says a marine biologist.

SailGP is being run in Lyttelton for the second time after Auckland pulled out of hosting the event.

But the first day of racing was abandoned entirely on Saturday after a dolphin was sighted on the course, delaying the start for two hours.

Last year, two other dolphins were seen within 300 metres of boats.

The second day of racing was due to get under way at 3pm Sunday.

Otago University zoology professor emeritus Liz Slooten said it was normal for Hector's dolphins to be around the harbour at this time of year.

Hector's dolphins are listed by the Department of Conservation as nationally vulnerable. Photo: Steve Dawson

"This was totally predictable."

Two of her colleagues from Otago University were on an expert panel discussing the issue ahead of last year's race.

"They already said, 'look, if you absolutely must do it in Lyttelton Harbour then you should do it in the middle of winter'."

Slooten said she was pleased to hear Sir Russell Coutts wanted to move the event to Wellington or Queenstown next year.

It was a poor decision from Christchurch officials to host the races, she said.

"This just seems to be a really bad bet, especially because these dolphins are actually very important economically to the Canterbury region.

"There's a lot of dolphin tourism on Akaroa Harbour. Really you don't want to kill the goose that laid the golden egg."

There was huge public interest behind the mammals because they were native to Aotearoa and endangered, she said.

SailGP has been contacted for comment.

SailGP managing director Andy Thompson earlier said the event had a "robust" marine mammal management plan.

Saturday was a "tough day" but conditions were looking "really top end" for Sunday, he said.

"Hopefully the F50s will be out there ripping around and we can send the fans home super happy."